It is a letter written with the intention, among other things, of thanking the Philippians for the monetary help they sent him.
But taking advantage of the occasion, the apostle addresses other issues and makes some confessions.

Source

I wait anxiously and hope that nothing will be ashamed.

On the contrary, with all the determination of always, also now Christ will be magnified in my body, both by life and by death;

because for me to live is Christ and dying is benefit.

If he continues to live in the body, I will have fruit of my work.

And I no longer know what to choose!

I am pressured on both sides: I want to leave and be with Christ, which is much better;

however, it is more necessary, because of you, to remain in the body.

Convinced of that, I know that I will remain and continue with all of you, for your progress and joy in the faith, so that, in my presence, again the withdrawal of you in Christ Jesus will transcend for me.

(Philippians 1: 20-26, NIV).

Paul was imprisoned when he wrote the epistle to the church in Philippi (Philippians 1:13).

He did not know if he was going to be sentenced to death or acquitted and remain alive.

He faced the reality of knowing that perhaps his days were numbered.

And, instead of going into despair, what did he do?

He faced this with maturity.

By declaring - for me to live is Christ and to die is gain, he meant that he did not fear death, because, if he lived for Christ, he was certain that he would obtain eternal life.

Then, death would be gain, because not only would it be the opportunity to be with Christ eternally, but also to rest from all his hardships.

Then, he remains without knowing with certainty what to choose: To die and to be with Christ or to remain alive to preach to the brothers.

The way you solve this dilemma is impressive.

He did not think only of himself, he did not have a selfish attitude.

Despite knowing that leaving and being with Christ was much better for him, he thought that he would be more optos in the Kingdom if he remained alive for progress and joy in the faith of the brothers.

Being convinced that the Lord also thought so, he was certain that he would be liberated and return to them.

We can learn great lessons with these attitudes of the apostle:

We should not fear death, if we really live for Christ, that is, if we live in a manner worthy of the Gospel (Philippians 1:27).

Source

"We, therefore, trust and prefer to be absent from the body and live with the Lord (2 Corinthians 5: 8), we must not act in a selfish way.

The good Christian does not only think about what is best for himself, but what is best for the edification of the Christian community (the church of Christ).